It's under control

The data fundamentals are in place, so let's look at a feature we'll be using for the first time in this application: the Controller. Not a view controller this time, but the over-arching application controller we talked about in our design:

// app/controller/Root.js
Ext.define('Postcard.controller.Root', {
    extend: 'Ext.app.Controller',

    routes: {
        'home': 'onHome',
        '': 'checkLogin'
    },

    onLaunch: function() {
        this.checkLogin();
    },

    checkLogin: function() {
        if(!window.localStorage.getItem('loggedin')) {
            this.loginWindow = Ext.create('Postcard.view.login.Login');
        } else {
            Ext.create('Postcard.view.main.Main');
        }
    },

    onHome: function() {
        if(this.loginWindow) {
            this.loginWindow.destroy();
        }

        this.checkLogin();
    }
});

In previous examples, app/Application.js has been responsible for creating the viewport that represents the main view of...